In reply to Removed User:
i decided to buy the arc as my gamma was a bit botched following the battery compartment breaking.
My initial views of the arc are - its heavier than the other ones but also feels more robust. Having the battery compartment at the back is great as its more balanced than the (weird) manta.
Taking two AA batteries is great compared to AAA as already mentioned.
The main beam is powerful enough and transitions nicely between modes. The side LEDs give a broad close up light which is better than that of the gamma having only one side LED.
Overall im impressed and look foreward to using it out on the trail when its dark next.